The issue normally referred to in the context of the high incidence of respiratory illness in Ireland is the high prevalence of asthma here. This was confirmed in a study of asthma in Ireland conducted by Allen and Hanburys in conjunction with the Asthma Society of Ireland in 2001. This research extended a previous study carried out in seven European countries in 1999, which confirmed that there are variations in asthma prevalence among EU countries. Certain environmental issues such as smoking and workplace exposure to respiratory irritants are contributory factors in this respect, as is the fact that better diagnostic techniques are being used which identify asthma sufferers to a greater degree than before.